<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
  <!-- 准备好一个“容器” -->
  <div id="test"></div>

  <!-- 引入react核心库 -->
  <script type="text/javascript" src="../js/react.development.js"></script>
  <!-- 引入react-dom，用于支持react操作DOM -->
  <script type="text/javascript" src="../js/react-dom.development.js"></script>
  <!-- 引入babel，用于将jsx转为js -->
  <script type="text/javascript" src="../js/babel.min.js"></script>

  <script type="text/babel">
    //创建组件
    class Login extends React.Component {

     //初始化状态
      state = {
        username: '', //用户名
        password: '' //密码
      }

      //保存用户名到状态中
      saveUsername = (event) => {
        this.setState({username: event.target.value})
      }

      //保存密码到状态中
      savePassword = (event) => {
        this.setState({password: event.target.value})
      }

      //表单提交的回调
      handleSubmit = (event) => {
        event.preventDefault() //阻止表单提交
        const {username, password} = this.state
        alert(`你输入的用户名是：${username},你输入的密码是：${password}`)
      }

      render() {
        return (
                <form onSubmit={this.handleSubmit}>
                  用户名：<input onChange={this.saveUsername} type="text" name="username"/>
                  密码：<input onChange={this.savePassword} type="password" name="password"/>
                  <button>登录</button>
                </form>
        )
      }
    }

    //渲染组件
    ReactDOM.render(<Login/>, document.getElementById('test'))
  </script>

</body>
</html>